The present invention relates to a new and improved construction of a circuit arrangement in an electrical device which contains a load supplied with a direct-current voltage of lesser quality and electronic components supplied with a direct-current voltage of greater quality, especially in a timing relay, for supplying the device with energy from an alternating-current network by means of a transformer or voltage divider, which can be connected with such network and a subsequently connected rectifier arrangement.
The heretofore known timing relays were designed for instance previously either with a non-stabilized supply or with completely stabilized supply. The timing relays equipped with non-stabilized supply have the advantage that the relay supply can be produced more economically. On the other hand as far as the timing relay itself is concerned there is present the drawback that the relay-operating voltage range of 0.8 . . . 1.1 U.sub.n (U.sub.n signifies the rated operating voltage) according to operating class C of IEC 2552 can only be realized with difficulty or great expenditure and due to the non-stabilized supply voltage and its ripples the timing accuracy of the timing relay is faulty. If there is provided a large charging capacitor in order to reduce the ripples i.e. for smoothing purposes, then the time needed for the timing relay to again assume a preparatory state is increased, so that the field of application of the relay in operation is impaired. In the case of timing relays with completely stabilized supply the operating class C can be realized without difficulty and the timing accuracy is satisfactory. However, the supply is expensive and complicated and to realize a faultless complete stabilization there is required for the supply circuit a large charging capacitor which impairs the operational readiness of a completely stabilized time relay.
In the case of a timing relay the electromechanical relay, which can be operated with a direct current supply possessing a large amount of ripples and provided that one does not drop below the holding current, constitutes the load which can be supplied with a direct-current voltage of lesser quality and the timing circuit with the RC-element form the electronic components of the previously mentioned electrical device which are to be supplied with a direct-current voltage of greater quality i.e. a constant direct-current voltage with less ripples. in such electrical devices there are thus present the same or similar defects as with the previously discussed timing relay. In summation then, electrical devices of the previously mentioned type with a non-stabilized power supply are generally inexpensive to fabricate but less accurate and therefore at the present time unsatisfactory in operation, and those with completely stabilized supply expensive to manufacture but then also accurate in operation. Furthermore, with such electrical devices the entire infed power must be converted to heat, so that a pronounced heating of both the load as well as also the electronic components can impair the proper functioning of the device and that disturbing or fault pulses can be delivereed from the network via the supply, which then must be suppressed in order to eliminate operational errors.